1. Field of the Invention
The invention relates to biodegradable, nontoxic compositions which can be used for cleaning hard surfaces such as metal, wood, and plastic and can also be used for removing paint from metal and wood. After cleaning a surface, the surface can be rinsed with water to remove any residual solvent since the composition is water miscible.
2. Background of the Invention
The prior art contains a multitude of compositions for cleaning hard surfaces, such as metal and wood. For example, U.S. Pat. Nos. 5,084,200; 5,230,821; 5,415,800; and 5,672,579 disclose cleaning compositions containing a mixture of dimethyl esters of succinic acid, glutaric acid and adipic acid. Such compositions have further been disclosed for use as paint removers in U.S. Pat. No. 4,780,235. While such compositions do exhibit desirable biodegradability properties, they have limited water solubility, typically about 5% at room temperature. As a result, it is necessary to include additional components, such as surfactants, emulsifiers and organic solvent solubilizers to make the compositions acceptable as cleansers.
WO 99/06520 discloses aqueous microemulsions for cleaning applications containing dibasic esters. Such compositions exhibit two disadvantages. First, they include emulsifiers which are expensive. Second, the dibasic esters come out of solution when the composition is diluted with water.
Compositions suitable for cleaning hard surfaces such as metallic, wood and plastic surfaces are desired which are miscible with water at room temperature and which do not require the addition of surfactants, emulsifiers and organic solvent solubilizers.
An aqueous composition suitable for cleaning hard surfaces, such as a metallic, wood, and plastic, contains at least one carboxylic acid diester and at least one fatty acid salt. The carboxylic acid diester may be represented by the formula:
R1COOxe2x88x92X+xe2x80x83xe2x80x83(I)
wherein R1 is a C6 to C19 hydrocarbyl group, optionally substituted with one or more hydroxyl or C1-C5 hydrocarbyl groups; and X is ammonium or an alkali metal. The carboxylic acid diester may be represented by the formula:
ROOC(CH2)nCOORxe2x80x2xe2x80x83xe2x80x83(II)
wherein R and Rxe2x80x2 are independently selected from a C1 to C8 alkyl group and n is from 1 to 8. The composition may be prepared by dissolving the carboxylic diester in a saturated solution of the fatty acid salt.
The composition of the invention is water miscible at room temperature and temperatures above room temperature.
In addition to being non-toxic and biodegradable, the composition of the invention is inexpensive to prepare and being miscible with water does not require the addition of expensive surfactants, emulsifiers and solubilizers to render the composition water soluble. In addition, since the composition of the invention does not require regulated solvents, one would expect no restrictions on shipping or storage.